Rrh^tm1Ght

Using homologous recombination in ES cells, a targeting vectir replaced a 4.3-kb fragment starting at the initiator methionine in exon 1 and a part of intron 1 of a mouse Rrh genomic fragment with a LacZ-coding region followed by a neomycin resistance cassette (PGK-Neo). Immunoblot analysis on retinal pigment epithelium (RPE) homogenates and immunohistochemistry of eyecup sections confirmed absence of protein in homozygous mice. It is a null allele. (J:256777)